Systems and methods for image data processing in computerized tomography

ABSTRACT

The present disclosure relates to systems and methods for image data processing. A first correction coefficient corresponding to a first collimation width of a collimator of a scanner may be obtained. The collimator may have a collimation width being adjustable. A relationship between scattered radiation intensities and collimation widths may be obtained. A relationship between correction coefficients and collimation widths may be determined based on the first correction coefficient, the first collimation width, and the relationship between scattered radiation intensities and collimation widths. A target collimation width of the collimator may be obtained. A target correction coefficient may be determined based on the target collimation width and the relationship between correction coefficients and collimation widths.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Application No.PCT/CN2017/088569, filed on Jun. 16, 2017. The disclosure of theabove-referenced application is expressly incorporated herein byreference in its entirety.

TECHNICAL FIELD

The present disclosure generally relates to image data processing incomputerized tomography (CT), and more particularly, to systems andmethods for modifying image data related to a scanning based on acollimation width of the scanning.

BACKGROUND

A collimator is an importation component of a CT system. The collimatoris positioned between an X-ray source and the scanned object (e.g. apatient) to control the scanning (e.g., a scanning region, a slicethickness). To improve imaging quality, image data collected in the CTsystem may be modified before image reconstruction. The modification ofthe image data may be associated with characteristics of the collimator,such as a collimation width. Thus, it may be desirable to developsystems and methods that modify image data based on the collimationwidth of the collimator.

SUMMARY

According to an aspect of the present disclosure, a system is provided.The system may include a scanner having a collimator, at least oneprocessor, and at least one storage device storing a set ofinstructions. The collimator may have a collimation width beingadjustable. The set of instructions, when executed by the at least oneprocessor, cause the system to perform the following operations. Thesystem may obtain a relationship between correction coefficients andcollimation widths. The system may obtain a target collimation width ofthe collimator. The system may determine a target correction coefficientbased on the target collimation width and the relationship betweencorrection coefficients and collimation widths.

In some embodiments, the set of instructions, when executed by the atleast one processor, cause the system to perform the followingoperations. The system may obtain image data related to a scanning withthe target collimation width. The system may modify the image data basedon the target correction coefficient.

In some embodiments, the set of instructions, when executed by the atleast one processor, cause the system to perform the followingoperations. The system may obtain a first correction coefficient, thefirst correction coefficient corresponding to a first collimation widthof the collimator. The system may obtain a relationship betweenscattered radiation intensities and collimation widths. The system maydetermine the relationship between correction coefficients andcollimation widths based on the first correction coefficient, the firstcollimation width, and the relationship between scattered radiationintensities and collimation widths.

In some embodiments, when executed by the at least one processor, causethe system to save the determined relationship between correctioncoefficients and collimation widths to the one or more storage devices.

In some embodiments, when executed by the at least one processor, causethe system to perform the following operations. The system may instructthe scanner to scan a first object with the first collimation width. Thesystem may obtain image data related to the first object based on thescanning of the first object. The system may process the image datarelated to the first object. The system may reconstruct an image of thefirst object based on the processed image data related to the firstobject. The system may determine the first correction coefficientcorresponding to the first collimation width based on the reconstructedimage of the first object.

In some embodiments, the first object may be a water phantom.

In some embodiments, when executed by the at least one processor, causethe system to instruct the scanner to scan air with the firstcollimation width.

In some embodiments, when executed by the at least one processor, causethe system to perform the following operations. The system may instructthe scanner to perform a first scanning of a second object with a secondcollimation width. The system may obtain a first radiation intensitybased on the first scanning of the second object. The system mayinstruct the scanner to change the collimation width from the secondcollimation width to a third collimation width. The system may instructthe scanner to perform a second scanning of the second object with thethird collimation width. The system may obtain a second radiationintensity based on the second scanning of the second object. The systemmay determine the relationship between radiation intensities andcollimation widths based on the second collimation width, the firstradiation intensity, the third collimation width, and the secondradiation intensity. The system may determine the relationship betweenscattered radiation intensities and collimation widths based on thedetermined relationship between radiation intensities and collimationwidths.

In some embodiments, the determination of the relationship betweenradiation intensities and collimation widths based on the secondcollimation width, the first radiation intensity, the third collimationwidth, and the second radiation intensity may be performed according toa curve fitting technique.

In some embodiments, when executed by the at least one processor, causethe system to determine a primary radiation intensity of the secondobject based on the relationship between radiation intensities andcollimation widths.

In some embodiments, when executed by the at least one processor, causethe system to perform the following operations. The system may obtain arelationship between collimation widths and ratios of scatteredradiation intensities over the primary radiation intensity of the secondobject. The system may designate the relationship between collimationwidths and ratios of scattered radiation intensities over the primaryradiation intensity of the second object as the relationship betweenscattered radiation intensities and collimation widths.

According to a further aspect of the present disclosure, acomputer-implemented method for image data processing may include one ormore of the following operations performed by at least one processor. Atleast one processor may obtain a relationship between correctioncoefficients and collimation widths. The at least one processor mayobtain a target collimation width of the collimator of a scanner. The atleast one processor may determine a target correction coefficient basedon the target collimation width and the relationship between correctioncoefficients and collimation widths.

According to another aspect of the present disclosure, a non-transitorymachine-readable storage medium may include instructions. When thenon-transitory machine-readable storage medium accessed by at least oneprocessor of a system, the instructions may cause the system to performone or more of the following operations. The system may obtain arelationship between correction coefficients and collimation widths. Thesystem may obtain a target collimation width of the collimator. Thesystem may determine a target correction coefficient based on the targetcollimation width and the relationship between correction coefficientsand collimation widths.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure is further described in terms of exemplaryembodiments. These exemplary embodiments are described in detail withreference to the drawings. The drawings are not to scale. Theseembodiments are non-limiting exemplary embodiments, in which likereference numerals represent similar structures throughout the severalviews of the drawings, and wherein:

FIG. 1 is a schematic diagram illustrating an exemplary CT systemaccording to some embodiments of the present disclosure;

FIG. 2 is a schematic diagram illustrating hardware and/or softwarecomponents of an exemplary computing device according to someembodiments of the present disclosure;

FIG. 3 is a schematic diagram illustrating hardware and/or softwarecomponents of an exemplary mobile device according to some embodimentsof the present disclosure;

FIG. 4A is schematic diagram illustrating an exemplary scanningaccording to some embodiments of the present disclosure;

FIG. 4B is schematic diagram illustrating an exemplary radiationintensity distribution according to some embodiments of the presentdisclosure;

FIG. 5 is a block diagram illustrating an exemplary processing engineaccording to some embodiments of the present disclosure;

FIG. 6 is a block diagram illustrating an exemplary processing moduleaccording to some embodiments of the present disclosure;

FIG. 7 is a flowchart illustrating an exemplary process for imagegeneration in computerized tomography according to some embodiments ofthe present disclosure;

FIG. 8 is a flowchart illustrating an exemplary process for processingimage data in computerized tomography according to some embodiments ofthe present disclosure;

FIG. 9 is a flowchart illustrating an exemplary process for determininga correction coefficient corresponding to a collimation width accordingto some embodiments of the present disclosure; and

FIG. 10 is a flowchart illustrating an exemplary process for determiningthe relationship between collimation widths and scattered radiationintensities according to some embodiments of the present disclosure.

DETAILED DESCRIPTION

In the following detailed description, numerous specific details are setforth by way of examples in order to provide a thorough understanding ofthe relevant disclosure. However, it should be apparent to those skilledin the art that the present disclosure may be practiced without suchdetails. In other instances, well known methods, procedures, systems,components, and/or circuitry have been described at a relativelyhigh-level, without detail, in order to avoid unnecessarily obscuringaspects of the present disclosure. Various modifications to thedisclosed embodiments will be readily apparent to those skilled in theart, and the general principles defined herein may be applied to otherembodiments and applications without departing from the spirit and scopeof the present disclosure. Thus, the present disclosure is not limitedto the embodiments shown, but to be accorded the widest scope consistentwith the claims.

It will be understood that the term “system,” “engine,” “unit,”“module,” and/or “block” used herein are one method to distinguishdifferent components, elements, parts, section or assembly of differentlevel in ascending order. However, the terms may be displaced by otherexpression if they may achieve the same purpose.

Generally, the word “module,” “unit,” or “block,” as used herein, refersto logic embodied in hardware or firmware, or to a collection ofsoftware instructions. A module, a unit, or a block described herein maybe implemented as software and/or hardware and may be stored in any typeof non-transitory computer-readable medium or other storage device. Insome embodiments, a software module/unit/block may be compiled andlinked into an executable program. It will be appreciated that softwaremodules can be callable from other modules/units/blocks or fromthemselves, and/or may be invoked in response to detected events orinterrupts. Software modules/units/blocks configured for execution oncomputing devices (e.g., processor 201 as illustrated in FIG. 2) may beprovided on a computer readable medium, such as a compact disc, adigital video disc, a flash drive, a magnetic disc, or any othertangible medium, or as a digital download (and can be originally storedin a compressed or installable format that needs installation,decompression, or decryption prior to execution). Such software code maybe stored, partially or fully, on a storage device of the executingcomputing device, for execution by the computing device. Softwareinstructions may be embedded in a firmware, such as an EPROM. It will befurther appreciated that hardware modules/units/blocks may be includedof connected logic components, such as gates and flip-flops, and/or canbe included of programmable units, such as programmable gate arrays orprocessors. The modules/units/blocks or computing device functionalitydescribed herein may be implemented as software modules/units/blocks,but may be represented in hardware or firmware. In general, themodules/units/blocks described herein refer to logicalmodules/units/blocks that may be combined with othermodules/units/blocks or divided into sub-modules/sub-units/sub-blocksdespite their physical organization or storage.

It will be understood that when a unit, engine, module or block isreferred to as being “on,” “connected to,” or “coupled to” another unit,engine, module, or block, it may be directly on, connected or coupledto, or communicate with the other unit, engine, module, or block, or anintervening unit, engine, module, or block may be present, unless thecontext clearly indicates otherwise. As used herein, the term “and/or”includes any and all combinations of one or more of the associatedlisted items.

The terminology used herein is for the purposes of describing particularexamples and embodiments only, and is not intended to be limiting. Asused herein, the singular forms “a,” “an,” and “the” may be intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “include” and/or“comprise,” when used in this disclosure, specify the presence ofintegers, devices, behaviors, stated features, steps, elements,operations, and/or components, but do not exclude the presence oraddition of one or more other integers, devices, behaviors, features,steps, elements, operations, components, and/or groups thereof.

Provided herein are systems and components for non-invasive imaging,such as for disease diagnosis or research purposes. In some embodiments,the imaging system may be a computed tomography (CT) system, an emissioncomputed tomography (ECT) system, an X-ray photography system, apositron emission tomography (PET) system, or the like, or anycombination thereof. For illustration purposes, the disclosure describessystems and methods for CT image data processing. The followingdescription is provided to help better understand CT image dataprocessing. The term “image” used in this disclosure may refer to a 2Dimage, a 3D image, or a 4D image. The term “image data” used in thisdisclosure may refer to CT data and projection data corresponding to theCT data. This is not intended to limit the scope the present disclosure.For persons having ordinary skills in the art, a certain amount ofvariations, changes, and/or modifications may be deducted under theguidance of the present disclosure. Those variations, changes, and/ormodifications do not depart from the scope of the present disclosure.

An aspect of the present disclosure relates to systems and methods formodifying image data related to a scanning based on a collimation widthof the scanning. A correction coefficient corresponding to thecollimation width of the scanning may be determined to modify the imagedata. A first correction coefficient corresponding to a firstcollimation width may be determined by performing a scanning with thefirst collimation width. A target correction coefficient correspondingto a target collimation width may be determined based on the firstcollimation width, the first correction coefficient, and a relationshipbetween radiation intensities and collimation widths. One of thepurposes of the method is to determine the target correction coefficientcorresponding to the target collimation width without performing ascanning with the target collimation width. As such, correctioncoefficients corresponding to the collimation widths in the CT systemmay be determined efficiently and quickly.

FIG. 1 is a schematic diagram illustrating an exemplary CT system 100according to some embodiments of the present disclosure. As shown, theCT system 100 may include a CT scanner 110, a network 120, one or moreterminals 130, a processing device 140, and a database 150.

The CT scanner 110 may include a gantry 111, a detector 112, a detectingregion 113, a table 114, a radioactive scanning source 115, and acollimator 116. The gantry 111 may be configured to support the detector112 and the radioactive scanning source 115. A subject may be placed onthe table 114 for scanning. The radioactive scanning source 115 may emitradioactive rays to the subject. The collimator 116 may be positionedbetween the radioactive scanning source 115 and the detector 112. Thecollimator 116 may control the scanning region of the radioactive raysgenerated by the radioactive scanning source 115. The detector 112 maydetect radiation events (e.g., gamma photons) emitted from the detectingregion 113. In some embodiments, the detector 112 may include one ormore detector units. The detector units may include a scintillationdetector (e.g., a cesium iodide detector), a gas detector, etc. Thedetector unit may include a single-row detector and/or a multi-rowsdetector.

The network 120 may include any suitable network that can facilitateexchange of information and/or data for the CT system 100. In someembodiments, one or more components of the CT system 100 (e.g., the CTscanner 110, the terminal 130, the processing device 140, the database150, etc.) may communicate information and/or data with one or moreother components of the CT system 100 via the network 120. For example,the processing device 140 may obtain image data from the CT scanner 110via the network 120. As another example, the processing device 140 mayobtain user instructions from the terminal 130 via the network 120. Thenetwork 120 may be and/or include a public network (e.g., the Internet),a private network (e.g., a local area network (LAN), a wide area network(WAN))), a wired network (e.g., an Ethernet network), a wireless network(e.g., an 802.11 network, a Wi-Fi network), a cellular network (e.g., aLong Term Evolution (LTE) network), a frame relay network, a virtualprivate network (“VPN”), a satellite network, a telephone network,routers, hubs, switches, server computers, and/or any combinationthereof. Merely by way of example, the network 120 may include a cablenetwork, a wireline network, a fiber-optic network, a telecommunicationsnetwork, an intranet, a wireless local area network (WLAN), ametropolitan area network (MAN), a public telephone switched network(PSTN), a Bluetooth™ network, a ZigBee™ network, a near fieldcommunication (NFC) network, or the like, or any combination thereof. Insome embodiments, the network 120 may include one or more network accesspoints. For example, the network 120 may include wired and/or wirelessnetwork access points such as base stations and/or internet exchangepoints through which one or more components of the CT system 100 may beconnected to the network 120 to exchange data and/or information.

The terminal(s) 130 may include a mobile device 130-1, a tablet computer130-2, a laptop computer 130-3, or the like, or any combination thereof.In some embodiments, the mobile device 130-1 may include a smart homedevice, a wearable device, a mobile device, a virtual reality device, anaugmented reality device, or the like, or any combination thereof. Insome embodiments, the smart home device may include a smart lightingdevice, a control device of an intelligent electrical apparatus, a smartmonitoring device, a smart television, a smart video camera, aninterphone, or the like, or any combination thereof. In someembodiments, the wearable device may include a bracelet, a footwear,eyeglasses, a helmet, a watch, clothing, a backpack, a smart accessory,or the like, or any combination thereof. In some embodiments, the mobiledevice may include a mobile phone, a personal digital assistance (PDA),a gaming device, a navigation device, a point of sale (POS) device, alaptop, a tablet computer, a desktop, or the like, or any combinationthereof. In some embodiments, the virtual reality device and/or theaugmented reality device may include a virtual reality helmet, virtualreality glasses; a virtual reality patch; an augmented reality helmet;augmented reality glasses, an augmented reality patch, or the like, orany combination thereof. For example, the virtual reality device and/orthe augmented reality device may include a Google Glass™, an OculusRift™, a Hololens™, a Gear VR™, etc. In some embodiments, theterminal(s) 130 may be part of the processing device 140.

The processing device 140 may process data and/or information obtainedfrom the CT scanner 110, the terminal 130, and/or the database 150.

In some embodiments, the processing device 140 may be a single server ora server group. The server group may be centralized or distributed. Insome embodiments, the processing device 140 may be local or remote. Forexample, the processing device 140 may access information and/or datastored in the CT scanner 110, the terminal 130, and/or the database 150via the network 120. As another example, the processing device 140 maybe directly connected to the CT scanner 110, the terminal 130 and/or thedatabase 150 to access stored information and/or data. In someembodiments, the processing device 140 may be implemented on a cloudplatform. Merely by way of example, the cloud platform may include aprivate cloud, a public cloud, a hybrid cloud, a community cloud, adistributed cloud, an inter-cloud, a multi-cloud, or the like, or anycombination thereof. In some embodiments, the processing device 140 maybe implemented by a computing device 200 having one or more componentsas illustrated in FIG. 2.

The database 150 may store data, instructions, and/or any otherinformation. In some embodiments, the database 150 may store dataobtained from the terminal 130 and/or the processing device 140. In someembodiments, the database 150 may store data and/or instructions thatthe processing device 140 may execute or use to perform exemplarymethods described in the present disclosure. In some embodiments, thedatabase 150 may include a mass storage, a removable storage, a volatileread-and-write memory, a read-only memory (ROM), or the like, or anycombination thereof. Exemplary mass storage may include a magnetic disk,an optical disk, a solid-state drive, etc. Exemplary removable storagemay include a flash drive, a floppy disk, an optical disk, a memorycard, a zip disk, a magnetic tape, etc. Exemplary volatileread-and-write memory may include a random access memory (RAM).Exemplary RAM may include a dynamic RAM (DRAM), a double date ratesynchronous dynamic RAM (DDR SDRAM), a static RAM (SRAM), a thyristorRAM (T-RAM), and a zero-capacitor RAM (Z-RAM), etc. Exemplary ROM mayinclude a mask ROM (MROM), a programmable ROM (PROM), an erasableprogrammable ROM (EPROM), an electrically erasable programmable ROM(EEPROM), a compact disk ROM (CD-ROM), and a digital versatile disk ROM,etc. In some embodiments, the database 150 may be implemented on a cloudplatform. Merely by way of example, the cloud platform may include aprivate cloud, a public cloud, a hybrid cloud, a community cloud, adistributed cloud, an inter-cloud, a multi-cloud, or the like, or anycombination thereof.

In some embodiments, the database 150 may be connected to the network120 to communicate with one or more other components of the CT system100 (e.g., the processing device 140, the terminal 130). One or morecomponents in the CT system 100 may access the data or instructionsstored in the database 150 via the network 120. In some embodiments, thedatabase 150 may be directly connected to or communicate with one ormore other components of the CT system 100 (e.g., the processing device140, the terminal 130). In some embodiments, the database 150 may bepart of the processing device 140.

FIG. 2 is a schematic diagram illustrating exemplary hardware and/orsoftware components of an exemplary computing device 200 on which theprocessing device 140 may be implemented according to some embodimentsof the present disclosure. As illustrated in FIG. 2, the computingdevice 200 may include a processor 210, a storage 220, an input/output(I/O) 230, and a communication port 240.

The processor 210 may execute computer instructions (e.g., program code)and perform functions of the processing device 140 in accordance withtechniques described herein. The computer instructions may include, forexample, routines, programs, objects, components, data structures,procedures, modules, and functions, which perform particular functionsdescribed herein. For example, the processor 210 may process image dataobtained from the CT scanner 110, the terminal 130, the database 150,and/or any other component of the CT system 100. In some embodiments,the processor 210 may include one or more hardware processors, such as amicrocontroller, a microprocessor, a reduced instruction set computer(RISC), an application specific integrated circuits (ASICs), anapplication-specific instruction-set processor (ASIP), a centralprocessing unit (CPU), a graphics processing unit (GPU), a physicsprocessing unit (PPU), a microcontroller unit, a digital signalprocessor (DSP), a field programmable gate array (FPGA), an advancedRISC machine (ARM), a programmable logic device (PLD), any circuit orprocessor capable of executing one or more functions, or the like, orany combinations thereof.

Merely for illustration, only one processor is described in thecomputing device 200. However, it should be noted that the computingdevice 200 in the present disclosure may also include multipleprocessors, thus operations and/or method steps that are performed byone processor as described in the present disclosure may also be jointlyor separately performed by the multiple processors. For example, if inthe present disclosure the processor of the computing device 200executes both operation A and operation B, it should be understood thatoperation A and operation B may also be performed by two or moredifferent processors jointly or separately in the computing device 200(e.g., a first processor executes operation A and a second processorexecutes operation B, or the first and second processors jointly executeoperations A and B).

The storage 220 may store data/information obtained from the CT scanner110, the terminal 130, the database 150, and/or any other component ofthe CT system 100. In some embodiments, the storage 220 may include amass storage, a removable storage, a volatile read-and-write memory, aread-only memory (ROM), or the like, or any combination thereof. Forexample, the mass storage may include a magnetic disk, an optical disk,a solid-state drives, etc. The removable storage may include a flashdrive, a floppy disk, an optical disk, a memory card, a zip disk, amagnetic tape, etc. The volatile read-and-write memory may include arandom access memory (RAM). The RAM may include a dynamic RAM (DRAM), adouble date rate synchronous dynamic RAM (DDR SDRAM), a static RAM(SRAM), a thyristor RAM (T-RAM), and a zero-capacitor RAM (Z-RAM), etc.The ROM may include a mask ROM (MROM), a programmable ROM (PROM), anerasable programmable ROM (EPROM), an electrically erasable programmableROM (EEPROM), a compact disk ROM (CD-ROM), and a digital versatile diskROM, etc. In some embodiments, the storage 220 may store one or moreprograms and/or instructions to perform exemplary methods described inthe present disclosure. For example, the storage 220 may store a programfor the processing device 140 for determining a regularization item.

The I/O 230 may input and/or output signals, data, information, etc. Insome embodiments, the I/O 230 may enable a user interaction with theprocessing device 140. In some embodiments, the I/O 230 may include aninput device and an output device. Examples of the input device mayinclude a keyboard, a mouse, a touch screen, a microphone, or the like,or a combination thereof. Examples of the output device may include adisplay device, a loudspeaker, a printer, a projector, or the like, or acombination thereof. Examples of the display device may include a liquidcrystal display (LCD), a light-emitting diode (LED)-based display, aflat panel display, a curved screen, a television device, a cathode raytube (CRT), a touch screen, or the like, or a combination thereof.

The communication port 240 may be connected to a network (e.g., thenetwork 120) to facilitate data communications. The communication port240 may establish connections between the processing device 140 and theCT scanner 110, the terminal 130, and/or the database 150. Theconnection may be a wired connection, a wireless connection, any othercommunication connection that can enable data transmission and/orreception, and/or any combination of these connections. The wiredconnection may include, for example, an electrical cable, an opticalcable, a telephone wire, or the like, or any combination thereof. Thewireless connection may include, for example, a Bluetooth™ link, aWi-Fi™ link, a WiMax™ link, a WLAN link, a ZigBee link, a mobile networklink (e.g., 3G, 4G, 5G, etc.), or the like, or a combination thereof. Insome embodiments, the communication port 240 may be and/or include astandardized communication port, such as RS232, RS485, etc. In someembodiments, the communication port 240 may be a specially designedcommunication port. For example, the communication port 240 may bedesigned in accordance with the digital imaging and communications inmedicine (DICOM) protocol.

FIG. 3 is a schematic diagram illustrating exemplary hardware and/orsoftware components of an exemplary mobile device 300 on which theterminal 130 may be implemented according to some embodiments of thepresent disclosure. As illustrated in FIG. 3, the mobile device 300 mayinclude a communication platform 310, a display 320, a graphicprocessing unit (GPU) 330, a central processing unit (CPU) 340, an I/O350, a memory 360, and a storage 390. In some embodiments, any othersuitable component, including but not limited to a system bus or acontroller (not shown), may also be included in the mobile device 300.In some embodiments, a mobile operating system 370 (e.g., iOS™,Android™, Windows Phone™) and one or more applications 380 may be loadedinto the memory 360 from the storage 390 in order to be executed by theCPU 340. The applications 380 may include a browser or any othersuitable mobile apps for receiving and rendering information relating toimage processing or other information from the processing device 140.User interactions with the information stream may be achieved via theI/O 350 and provided to the processing device 140 and/or othercomponents of the CT system 100 via the network 120.

To implement various modules, units, and their functionalities describedin the present disclosure, computer hardware platforms may be used asthe hardware platform(s) for one or more of the elements describedherein. A computer with user interface elements may be used to implementa personal computer (PC) or any other type of work station or terminaldevice. A computer may also act as a server if appropriately programmed.

FIG. 4A is schematic diagram illustrating an exemplary scanningaccording to some embodiments of the present disclosure. As shown inFIG. 4A, the radioactive scanning source 115 may emit radioactive rays420 to an object 430. In some embodiments, the radioactive rays 420 maybe X-rays. The object 430 may be an experimental object, an organ,tissue, or any body parts of a patient to be scanned. The collimator 116may be positioned between the radioactive scanning source 115 and theobject 430.

In some embodiments, the collimator 116 may include two collimatorplates that are separated from each other. The collimator plates may bemade of X-ray absorbing material, such as lead or tungsten. Theradioactive rays irradiated on the collimator plates may be absorbed,and the rest may reach the object 430. The collimator 116 may include aspace between the two collimator plates. The number of radiation raysirradiated on the object 430 may depend with the size of the space. Forexample, the number of radiation rays irradiated on the object 430 mayincrease with the increase in a distance between the two collimatorplates.

The radiation rays passing through the space between the two collimatorplates may pass through an isocenter surface 410. The isocenter surface410 refers to a surface that passes the rotation isocenter of the gantry110. In some embodiments, the isocenter surface 410 may be parallel withthe collimator plates. The radiation rays passing through the space 440may have an irradiation region on the isocenter surface 410. Acollimation width of the collimator 116 refers to the largest distancebetween two points in the irradiation region among any two points in theirradiation region. The collimation width of the collimator 116 maydepend with the distance between the two collimator plates. For example,the collimation width may increase with the increase in the distancebetween the two collimator plates.

The collimation width may be set manually by a user (e.g., a technician,a doctor, a nurse) via the terminal 130 or the processing device 140.Additionally or alternatively, the collimation width may be determinedby one or more components of the CT system 100. In some embodiments, theprocessing device 140 may determine a collimation width based on thedistance between the two collimator plates, a distance between theradioactive scanning source 115 and the collimator 116, and a distancebetween the radioactive scanning source 115 and the isocenter surface410. Merely by way of example, the processing device 140 may divide thedistance between the radioactive scanning source 115 and the isocentersurface 410 by the distance between the radioactive scanning source 115and the collimator 116 to obtain a quotient. The processing device 140may then determine the collimation width by multiplying the distancebetween the two collimator plates by the quotient. In some embodiments,the distance between the radioactive scanning source 115 and thecollimator 116 may be in a range of 180-210 mm (e.g., 190 mm). Thedistance between the radioactive scanning source 115 and the isocentersurface 410 may be in a range of 500-600 mm (e.g., 570 mm).

The radioactive rays irradiated on the object 430 may pass through theobject 430, be absorbed by the object 430, or be scattered by the object430. The radioactive rays passing through the object 430 (e.g., aradioactive ray 420-2) are referred to herein as a primary radiation.The radiation rays scattered by the object 430 (e.g., a radioactive ray420-1) are referred to herein as a scattered radiation. Differentscanned objects or different parts of a scanned object may have a sameabsorption rate or different absorption rates of radioactive rays.Different scanned objects or different parts of the scanned object mayhave a same scattering rate or different scattering rates of radioactiverays.

The radiations, including the primary radiation and the scatteredradiation, may be detected by the detector 112. In some embodiments, theprocessing device 140 may determine the radiation intensity of theprimary radiation and the scattered radiation based on the radiationsreceived by the detector 112. The radiation intensity may be equal to asum of a primary radiation intensity and a scattered radiationintensity. When the collimation width of the collimator 116 changes, thescattered radiation intensity may change, but the primary radiationintensity may remain constant. For example, the scattered intensity mayincrease with the increase in the collimation width. Accordingly, theradiation intensity may increase with the increase in the collimationwidth.

It should be noted that the above descriptions are provided for thepurposes of illustration, and not intended to limit the scope of thepresent disclosure. For persons having ordinary skills in the art,various modifications and changes in the forms and details of theapplication of the above method and system may occur without departingfrom the principles of the present disclosure. For example, thecollimator 116 may be arranged in any position between the radioactivescanning source 115 and the object 430. As another example, thecollimator 116 may have any shape, size, and configuration. In someembodiments, the collimator 116 may be an integral plate with a hole. Aportion of the radioactive rays 420 may pass through the hole toirradiate the object 430. The amount of radioactive rays irradiated onthe object 430 may be related to the size of the hole. However, thosevariations and modifications also fall within the scope of the presentdisclosure.

FIG. 4B is schematic diagram illustrating an exemplary radiationintensity distribution according to some embodiments of the presentdisclosure. The X-axis corresponds to different parts of the object 430in the horizontal direction. The Y-axis corresponds to the radiationintensity. Curve 440 indicates a distribution of a total radiationintensity related to the object 430, including the radiation intensityof the primary radiation and the radiation intensity of the scatteredradiation. Curve 450 indicates a distribution of the radiation intensityof the primary radiation. Curve 460 indicates a distribution of theradiation intensity of the scattered radiation. The total radiationintensity may be determined by the processing device 140 based onradiations received by the detector 112. The total radiation intensityof the object 430 is equal to a sum of a scattered radiation intensityand a primary radiation intensity.

It should be noted that the examples of radiation intensitydistributions illustrated in FIG. 4B are provided for the purposes ofillustration, and not intended to limit the scope of the presentdisclosure. For persons having ordinary skills in the art, variousmodifications and changes in the forms and details of the application ofthe above method and system may occur without departing from theprinciples of the present disclosure. For example, the total radiationintensity, the scattered radiation intensity, and the primary radiationintensity may have any distribution pattern, respectively.

FIG. 5 is a block diagram illustrating an exemplary processing device140 according to some embodiments of the present disclosure. Theprocessing device 140 may include an acquisition module 510, a controlmodule 520, a storage module 530, and a processing module 540.

The acquisition module 510 may acquire image data. The acquisitionmodule 510 may acquire the image data from the detector 112. The imagedata may include CT data, projection data corresponding to the CT data,an image (e.g., a 2D image, a 3D image, a 4D image data). The image datamay include information elated to the radiations that pass throughand/or be scattered by an object. In some embodiments, the radioactivescanning source 115 may emit the radiations toward the object. Theradiations may pass through the object or be scattered by the object andmay attenuate during the transmission process. The attenuated radiationsmay be detected by the detector 112 and reflected in the image datatransmitted to the acquisition module 510. In some embodiments, theacquired image data may be transmitted to the storage module 530 forstorage.

The control module 520 may control operations of one or more componentsin the CT system 100, such as the acquisition module 510, the storagemodule 530, the processing module 540, and/or the CT scanner 110 (e.g.,by generating one or more control signals or parameters). For example,the control module 520 may control the acquisition module 510 to acquirea signal, the timing of the acquisition of the signal, etc. As anotherexample, the control module 520 may control the processing module 540 toprocess the image data acquired by the acquisition module 510. In someembodiments, the control module 520 may receive a real-time command orretrieve a predetermined command provided by a user (e.g., a doctor) tocontrol one or more operations of the acquisition module 510 and/or theprocessing module 540, In some embodiments, the control module 520 maycommunicate with one or more other modules of the processing device 140for exchanging information and/or data. In some embodiments, the controlmodule 520 may set one or more scanning parameters. The scanningparameters may include a distance between the radioactive scanningsource 115 and the collimator 116, a distance between the radioactivescanning source 115 and a scanned object, a distance between thecollimator 116 and the detector 112, a collimation width of thecollimator 116, a radiation dosage, or the like, or any combinationthereof.

The storage module 530 may store image data, control parameters,processed data generated by various modules of the processing device140, or the like, or a combination thereof. In some embodiments, thestorage 530 may store one or more programs and/or instructions that maybe executed by the processor(s) of the processing device 140 to performexemplary methods described in this disclosure. For example, the storage530 may store program(s) and/or instruction(s) that can be executed bythe processor(s) of the processing device 140 to perform the functionsthereof disclosed in this disclosure (e.g., acquiring image data,processing the image data, recontructing an image based on the imagedata or the processed image data). As another example, storage module530 may store a relationship between collimation widths and scatteredradiation intensities, a relationship between collimation widths andcorrection coefficients, and/or a relationship between collimationwidths and ratios of scattered radiation intensities over the primaryradiation intensity.

The processing module 540 may process information provided by variousmodules of the processing device 140. The processing module 540 mayprocess image data acquired by the acquisition module 510, image dataretrieved from the storage module 530, etc. For example, the processingmodule 540 may determine a correction coefficient corresponding to acollimation width of a scanning. Additionally or alternatively, theprocessing module 540 may modify image data associated with the scanningbased on the correction coefficient.

In some embodiments, the processing module 540 may reconstruct CT imagesbased on the image data according to a reconstruction algorithm,generate reports including one or more CT images and/or other relatedinformation, and/or perform any other function for image reconstructionin accordance with various embodiments of the present disclosure. Thereconstruction algorithm may include an iterative reconstructionalgorithm (e.g., a statistical reconstruction algorithm), a Fourierslice theorem algorithm, a filtered back projection (FBP) algorithm, afan-beam reconstruction algorithm, an analytic reconstruction algorithm,or the like, or any combination thereof.

In some embodiments, one or more modules illustrated in FIG. 5 may beimplemented in at least part of the exemplary CT system as illustratedin FIG. 1. For example, the acquisition module 510, the control module520, the storage module 530, and/or the processing module 540 may beintegrated into a console (not shown), Via the console, a user may setparameters for scanning an object (e.g., a collimation width of thecollimator), controlling imaging processes, controlling parameters forreconstruction of an image, viewing reconstructed images, etc. In someembodiments, the console may be implemented via the processing device140 and/or the terminal 130.

FIG. 6 is a block diagram illustrating an exemplary processing module540 according to some embodiments of the present disclosure. Theprocessing module 540 may include an acquisition unit 610, arelationship determination unit 620, a correction coefficientdetermination unit 630, and a correction unit 640. The processing module540 may be implemented on various components (e.g., the processor 210 ofthe computing device 200 as illustrated in FIG. 2).

The acquisition unit 610 may obtain image data related to a scanning.The image data may be obtained from other component in the CT system100, such as the storage device 150 or the storage module 430. The imagedata may be associated with the radiations that pass through and/or bescattered by a scanned object in the scanning.

The relationship determination unit 620 may obtain and/or determine oneor more relationships between parameters related to the CT system 100.The one or more relationships may include but are not limited to arelationship between collimation widths and scattered radiationintensities, a relationship between correction coefficients andcollimation widths, and/or a relationship between collimation widths andratios of scattered radiation intensities over the primary radiationintensity. In some embodiments, the relationship determination unit 620may obtain at least part of the one or more relationships from a storagedevice (e.g., the storage device 150, the storage 220). In someembodiments, the relationship determination unit 620 may determine atleast part of the one or more relationships based on data analyzing.

The correction coefficient determination unit 630 may determine acorrection coefficient corresponding to a collimation width of ascanning. In some embodiments, the correction coefficient determinationunit 630 may determine the correction coefficient corresponding to thecollimation width based a scanning of an object with the collimationwidth. For example, the correction coefficient determination unit 630may determine the correction coefficient corresponding to thecollimation width based on a reconstructed image generated based on thescanning with the collimation width. In some embodiments, the correctioncoefficient determination unit 630 may determine the correctioncoefficient corresponding to the collimation width based on arelationship between collimation widths and correction coefficients. Therelationship may be stored in a storage device (e.g., the storage device150, the storage 220). The relationship may be recorded in the form of atable, a drawing, a mathematical expression, etc. The correctioncoefficient determination unit 630 may retrieve the relationship fromthe storage device and determine the correction coefficientcorresponding to the collimation width based on the relationship.

The correction unit 640 may the correction unit 640 may modify imagedata based on a correction coefficient. In some embodiments, thecorrection unit 640 may modify the image data by multiplying the imagedata with the correction coefficient. For example, the image data mayinclude projection data related to the scanning. For illustrationpurpose, assuming that the correction coefficient is equal to eight, thecorrection unit 640 may obtain modified projection data that is equal toeight times of the projection data.

It should be noted that the above descriptions of the processing device140 and/or the processing module 540 are provided for the purposes ofillustration, and not intended to limit the scope of the presentdisclosure. For persons having ordinary skills in the art, variousmodifications and changes in the forms and details of the application ofthe above method and system may occur without departing from theprinciples of the present disclosure. In some embodiments, theprocessing module 540 may include one or more other modules. Forexample, the processing module 540 may include a storage module to storedata generated by the modules in the processing module 540. As anotherexample, the relationship determination unit 620 may include a radiationintensity determination subunit to determine a radiation intensityrelated to a scanning based on image data of a scanning. In someembodiments, one module may perform the functions of two or more modulesdescribed above. For example, the correction coefficient determinationunit 630 and the correction unit 640 may form a module to determine thecorrection coefficient and correction image data based on the determinedcorrection coefficient. However, those variations and modifications alsofall within the scope of the present disclosure.

FIG. 7 is a flowchart illustrating an exemplary process for imagegeneration in computerized tomography according to some embodiments ofthe present disclosure. In some embodiments, at least part of theprocess 700 may be performed by the processing device 140 (implementedin, for example, the computing device 200 shown in FIG. 2).

In 710, the control module 520 may set one or more scanning parameters.The scanning parameters may include a distance between the radioactivescanning source 115 and the collimator 116, a distance between theradioactive scanning source 115 and a scanned object, a distance betweenthe collimator 116 and the detector 112, a collimation width of thecollimator 116, a radiation dosage, or the like, or any combinationthereof. In some embodiments, the scanning parameters may be defaultparameters stored in a storage device (e.g., the storage device 150) orset by a user (e.g., a doctor) of the CT system 100. Alternatively oradditionally, the scanning parameters may be determined by one or morecomponents (e.g., the processing device 140) in the CT system 100. Insome embodiments, in 710, the control module 520 may set the collimationwidth of the collimator 116. The collimation width may be 2 mm, 5 mm, 10mm, 20 mm, 40 mm or any other suitable width.

In 720, the radioactive scanning source 115 may scan an object byemitting one or more radioactive rays. In some embodiments, theradioactive rays may be X-rays. The object may be an experimentalobject, an organ, tissue, or any body parts of a patient to be scanned.In some embodiments, some of the radioactive rays may pass through thespace between the collimator plates (having a width W), and the rest maybe absorbed by the collimator plates. The radioactive rays that passthrough the space between the collimator plates may be irradiated on theobject. The radioactive rays irradiated on the object may pass throughthe object or be scattered by the object. The radioactive rays passingthrough the object may be referred herein as primary radiations and theradiation rays scattered by the object may be referred herein asscattered radiations as described elsewhere in this disclosure (e.g.,FIG. 4A and the relevant descriptions).

In 730, the acquisition module 510 may obtain image data related to theobject based on the scanning. The image data may be associated with theradiations that pass through and/or be scattered by the object. Theradiations, which may include the primary radiations and the scatteredradiations, may attenuate during transmission process. The attenuatedradiations may be detected by the detector 112, and the image datarelated to the attenuated radiations may be obtained by the acquisitionmodule 510.

In 740, the processing device 140 (e.g., the processing module 540) mayprocess the image data. The image data processing may include one ormore data processing operations, such as data projection, datafiltering, data sequencing, data modifying, curve fitting. In someembodiments, the image data may be modified based on a correctioncoefficient of a Hounsfield unit (HU) value of a voxel (as referredherein as the correction coefficient). The correction coefficient mayindicate a relative ratio of an attenuation coefficient of the voxel toan attenuation coefficient of water. The HU value of the voxel may bedescribed according to Equation (1) below:

$\begin{matrix}{{{HU} = {{\frac{\mu - \mu_{water}}{\mu_{water}}*1000} = {{\mu*\frac{1000}{\mu_{water}}} - 1000}}},} & {{Equation}\mspace{14mu}(1)}\end{matrix}$where μ refers to the attenuation coefficient of the voxel, andμ_(water) refers to the attenuation coefficient of water.

The correction coefficient may be determined based on Equation (1) anddescribed according to Equation (2) below:

$\begin{matrix}{{C = \frac{1000}{\mu_{water}}},} & {{Equation}\mspace{14mu}(2)}\end{matrix}$where C refers to the correction coefficient of the HU value of thevoxel.

The correction coefficient may be associated with one or more scanningparameters described in connection with step 710. In some embodiments,the correction coefficient may be associated with the collimation widthof the collimator 116. For example, the correction coefficientscorresponding to different collimation widths may be different.

In some embodiments, the processing device 140 (e.g., the correctioncoefficient determination unit 630) may determine a correctioncoefficient corresponding to the collimation width of the scanning. Theprocessing device 140 (e.g., the correction unit 640) may also modifythe image data based on the correction coefficient. For example, theprocessing device 140 may determine the correction coefficientcorresponding to the collimation width based on a relationship betweencollimation widths and correction coefficients. The relationship betweencollimation widths and correction coefficients may be stored in astorage device (e.g., the storage device 150, the storage 220), and theprocessing device 140 may retrieve the relationship from the storagedevice. Alternatively or additionally, the relationship betweencollimation widths and correction coefficients may be determined by theprocessing device 140 based on experimental data. More descriptionsregarding the modifying image data based on the correction coefficientcorresponding to the collimation width may be found elsewhere in thepresent disclosure (e.g., FIG. 8 and the relevant descriptions).

In 750, the processing module 540 may reconstruct an image based on theprocessed (or modified) image data. The reconstructed image may includea 3D image, 4D image data, a 4D image, or the like, or any combinationthereof. The processing module 540 may reconstruct the image based onthe processed (or modified) image data according to a reconstructionalgorithm. The reconstruction algorithm may include an iterativereconstruction algorithm (e.g., a statistical reconstruction algorithm),a Fourier slice theorem algorithm, a filtered back projection (FBP)algorithm, a fan-beam reconstruction algorithm, an analyticreconstruction algorithm, or the like, or any combination thereof.

It should be noted that the above descriptions of process 700 areprovided for the purposes of illustration, and not intended to limit thescope of the present disclosure. For persons having ordinary skills inthe art, various modifications and changes in the forms and details ofthe application of the above method and system may occur withoutdeparting from the principles of the present disclosure. In someembodiments, one or more operations may be added or omitted. Forexample, step 750 may be omitted. As another example, an additionaloperation may be performed to display the reconstructed image on theterminal 130. However, those variations and

FIG. 8 is a flowchart illustrating an exemplary process for processingimage data in computerized tomography according to some embodiments ofthe present disclosure. In some embodiments, at least part of theprocess 800 may be performed by the processing device 140 (implementedin, for example, the computing device 200 shown in FIG. 2).

In 810, the correction coefficient determination unit 630 may obtain afirst correction coefficient corresponding to a first collimation width.The CT scanner 110 may scan an object with the first collimation width,and the correction coefficient determination unit 630 may determine thefirst correction coefficient corresponding to the first collimationwidth based on the scanning of the object. More descriptions regardingthe determination of the first correction coefficient corresponding tothe first collimation width may be found elsewhere in the presentdisclosure (e.g., FIG. 9 and the relevant descriptions)

In 820, the relationship determination unit 620 may obtain arelationship between collimation widths and scattered radiationintensities. The relationship may be recorded in the form of a table, adrawing, a mathematical expression, etc. For example, the relationshipmay be recorded in a table of collimation widths and their correspondingscattered radiation intensities (e.g., a look-up table) stored in astorage device (e.g., the storage device 150, the storage 220). Therelationship determination unit 620 may access the storage device andretrieve the relationship. As another example, the relationship may berecorded in a mathematical function. The mathematical function mayinclude at least two variables: the scattered radiation intensity andthe collimation width. Alternatively, the mathematical function mayinclude other variables that may affect the relationship betweencollimation widths and scattered radiation intensities, such as one ormore scanning parameters as described in connection with FIG. 7. Themathematical function may be a linear function, an inverse function, aquadratic function, a discontinuous function, a trigonometric functions,an injective function, a surjective function, or the like, or anycombination thereof. In some embodiments, the mathematical function maybe a linear function with the collimation width being an independentvariable and the scattered radiation intensity being a dependentvariable.

In some embodiments, the relationship determination unit 620 may obtainthe relationship between collimation widths and scattered radiationintensities from other component in the CT system 100, such as thestorage device 150 or the storage module 430. In some embodiments, therelationship determination unit 620 may determine the relationshipbetween collimation widths and scattered radiation intensities based onexperiment data. For example, the CT scanner 110 may perform anexperiment by scanning an experimental object with different collimationwidths. The processing device 140 may determine radiation intensitiescorresponding to the different collimation widths based on image datacollected by the detector 112. As another example, the processing device140 may simulate an experiment of scanning an experimental object withdifferent collimation widths and determine radiation intensitiescorresponding to the different collimation widths. The relationshipdetermination unit 620 may obtain the experimental data related to theperformed experiment or the simulated experiment and determine therelationship between collimation widths and scattered radiationintensities based on the experimental data. The determination of therelationship between collimation widths and scattered radiationintensities may include one or more data processing operations of theexperimental data. Exemplary data processing operations may include butare not limited to data sequencing, data filtering, curve fitting.

In some embodiments, the relationship between collimation widths andscattered radiation intensities may be determined based on arelationship between radiation intensities and collimation widths. Moredescriptions regarding the determination of the relationship betweencollimation widths and scattered radiation intensities of may be foundelsewhere in the present disclosure (e.g., FIG. 10 and the relevantdescriptions)

In 830, the relationship determination unit 620 may determine arelationship between correction coefficients and collimation widthsbased on the first correction coefficient, the first collimation width,and the relationship between collimation widths and scattered radiationintensities. For illustration purpose, the relationship betweencollimation widths and scattered radiation intensities may be describedaccording to Equation (3) below:S=f(w)  Equation (3),where S refers to the scattered radiation intensity, w refers to thecollimation width.

The correction coefficient of the image data may be determined based onthe u value of water according to Equation (2) as described elsewhere inthis disclosure (e.g., FIG. 7 and the relevant descriptions). The uvalue of water may be proportional to a radiation intensity (i.e., a sumof a scattered radiation intensity and a primary radiation intensity)received by the detector 112. The primary radiation intensity may have aconstant value, More descriptions regarding the determination of primaryradiation intensity may be found elsewhere in the present disclosure(e.g., FIG. 10 and the relevant descriptions). The relationship betweencollimation widths and radiation intensities may be described accordingto Equation (4) below:

$\begin{matrix}{{\frac{1000}{C_{w}} = {c^{*}\left( {{f(w)} + P} \right)}},} & {{Equation}\mspace{14mu}(4)}\end{matrix}$where C_(w) refers to the correction coefficient corresponding to thecollimation width w, P refers to the primary radiation intensity, crefers to a coefficient that may be determined according to Equation (5)below

$\begin{matrix}{{C = \frac{1000}{{C_{w\; 1}}^{*}\left( {{f\left( {w\; 1} \right)} + P} \right)}},} & {{Equation}\mspace{14mu}(5)}\end{matrix}$where w1 refers to the first collimation width, C_(w1) refers to thefirst correction coefficient corresponding to the first collimationwidth w1 (as described in connection with operation 810), f(w1) refersto the scattered radiation intensity corresponding to the firstcollimation width.

In 840, the acquisition unit 610 may obtain image data related to ascanning at a target collimation width. The image data may be obtainedfrom other component in the CT system 100, such as the storage device150 or the storage module 430. The image data may be associated with theradiations that pass through or be scattered by a scanned object in thescanning with the target collimation width.

In 850, the correction coefficient determination unit 630 may determinea target correction coefficient corresponding to the target collimationwidth based on the target collimation width, and the relationshipbetween correction coefficients and collimation widths. As described inconnection with operation 830, the relationship between collimationwidths and radiation intensities may be described according to Equation(4). The target correction coefficient may be determined based on thetarget collimation width and the Equation (4).

In 860, the correction unit 640 may modify the image data based on thetarget correction coefficient. In some embodiments, the correction unit640 may modify the image data by multiplying the image data with thetarget correction coefficient. For example, the image data may includeprojection data related to the scanning. For illustration purpose,assuming that the correction coefficient is equal to eight, thecorrection unit 640 may obtain modified projection data that is equal toeight times of the projection data.

It should be noted that the above descriptions of process 800 areprovided for the purposes of illustration, and not intended to limit thescope of the present disclosure. For persons having ordinary skills inthe art, various modifications and changes in the forms and details ofthe application of the above method and system may occur withoutdeparting from the principles of the present disclosure. However, thosevariations and modifications also fall within the scope of the presentdisclosure.

In some embodiments, the order of the operations in process 800 may bechanged. For example, 810 and 840 may be performed simultaneously. Insome embodiments, the relationship between collimation widths andcorrection coefficients may be stored in a storage device (e.g., thestorage device 150, the storage 220). The correction coefficientdetermination unit 630 may retrieve the relationship (e.g., a look-uptable) from the storage device and determine a correction coefficientcorresponding to a collimation width based on the retrievedrelationship. For example, a table of collimation widths and theircorresponding correction coefficients may be stored in the storagedevice. The correction coefficient determination unit 630 may determinethe correction coefficient corresponding to the collimation width bylooking up the table.

In some embodiments, in 820, the relationship determination unit 620 mayobtain a relationship between collimation widths and ratios of scatteredradiation intensities over the primary radiation intensity. In 830, therelationship determination unit 620 may determine the relationshipbetween correction coefficients and collimation widths based on thefirst correction coefficient, the first collimation width, and therelationship between relationship between collimation widths and ratiosof scattered radiation intensities over the primary radiation intensity.The relationship determination unit 620 may designate the relationshipbetween collimation widths and ratios of scattered radiation intensitiesover the primary radiation intensity of the second object as therelationship between scattered radiation intensities and collimationwidths. More descriptions regarding the determinations of therelationship between collimation widths and ratios of scatteredradiation intensities over the primary radiation intensity may be foundelsewhere in the present disclosure (e.g., FIG. 10 and the relevantdescriptions).

FIG. 9 illustrates a flowchart illustrating an exemplary process fordetermining a correction coefficient corresponding to a collimationwidth according to some embodiments of the present disclosure. In someembodiments, at least part of the process 900 may be performed by theprocessing device 140 (implemented in, for example, the computing device200 shown in FIG. 2), In some embodiments, operation 810 of the process800 may be performed according to one or more operations in the process900.

In 910, the CT scanner 110 may scan an experimental object with acollimation width. The collimation width may be 1 mm, 2 mm, 10 mm, 20mm, 40 mm or any suitable other number. More descriptions regarding thecollimation width may be found elsewhere in the present disclosure(e.g., FIGS. 4A and 7 and the relevant descriptions). In someembodiments, the experimental object may be a water phantom. Thediameter of the water phantom may be 100 mm, 180 mm, 200 mm, or anyother suitable number. The thickness of a wall of the water phantom maybe 1 mm, 2 mm, 3 mm, or any other suitable number.

In 920, the acquisition module 510 may obtain image data related to theexperimental object based on the scanning of the experimental object.The image data may be associated with radiations that pass through or bescattered by the object. More descriptions regarding the image data maybe found elsewhere in the present disclosure (e.g., FIG. 7 and therelevant descriptions).

In 930, the processing device 140 may process the obtained image data.The image data processing may include one or more data processingoperations, such as data projection, data filtering, data sequencing,data modifying. In some embodiments, the processing device 140 maymodify the image data related to the experimental object by removingnoise (e.g., a gain inhomogeneity, an intensity inhomogeneity, or anartifact).

In 940, the processing device 140 may reconstruct an image of theexperimental object based on the processed image data. The reconstructedimage may be a 3D image, 4D image data, a 4D image, or the like, or anycombination thereof. The processing module 540 may reconstruct the imagebased on the image data according to a reconstruction algorithm. Moredescriptions regarding the generation of the reconstructed image may befound elsewhere in the present disclosure (e.g., FIG. 7 and the relevantdescriptions).

In 950, the correction coefficient determination unit 630 may determinea correction coefficient corresponding to the collimation width based onthe reconstructed image. For example, the experimental object may be awater phantom, and the correction coefficient determination unit 630 mayobtain a sub-area of the reconstructed image of the water phantom. Thecorrection coefficient determination unit 630 may determine thecorrection coefficient based on pixel values of the pixels in thesubarea. The subarea may correspond to any part of the water phantom inthe reconstructed image. Merely by way of example, the subarea maycorrespond to a central area of the water phantom. The subarea may haveany regular shape (e.g., a circle, a rectangle, or a square) or anyirregular shape. In some embodiments, the correction coefficientdetermination unit 630 may determine a μ_(water) based on an averagepixel value of the pixels in the subarea. The correction coefficientdetermination unit 630 may then determine the correction coefficientcorresponding to the collimation width based on the μ_(water) accordingto Equation (2) as described elsewhere in this disclosure (e.g., FIG. 7and the relevant descriptions). For illustration purpose, assuming thatthe μ_(water) is equal to 125 HU, the correction coefficientcorresponding to the collimation width may be determined by dividing1000 by 125 and be equal to 8.

It should be noted that the above descriptions of process 900 areprovided for the purposes of illustration, and not intended to limit thescope of the present disclosure. For persons having ordinary skills inthe art, various modifications and changes in the forms and details ofthe application of the above method and system may occur withoutdeparting from the principles of the present disclosure. In someembodiments, one or more operations may be added or omitted. Forexample, additional operations may be performed before 910 to scan airand obtain image data related to the air based on the scanning of theair. The scanning of air may be performed by the CT scanner 110 with acollimation width that is same with the collimation width in 910. In930, the processing device 140 may modify the image data related toexperimental object based on the image data related to the air to removenoise caused by the air. In some embodiments, the CT scanner 110 mayperform the scanning of the experimental object or the air under aninstruction of the processing device 140 (e.g., an instruction sent bythe control module 520). However; those variations and modificationsalso fall within the scope of the present disclosure.

FIG. 10 illustrates a flowchart illustrating an exemplary process fordetermining the relationship between collimation widths and scatteredradiation intensities according to some embodiments of the presentdisclosure. In some embodiments, at least part of the process 1000 maybe performed by the processing device 140 (implemented in, for example,the computing device 200 shown in FIG. 2). In some embodiments,operation 820 of the process 800 may be performed according to one ormore operations in the process 1000.

In 1010, the CT scanner 110 may perform a first scanning by scanning anexperimental object with a first collimation width. In some embodiments,the experimental object may be a water phantom. More descriptionsregarding the collimation width and the experimental object may be foundelsewhere in the present disclosure (e.g., FIG. 9 and the relevantdescriptions).

In 1020, the relationship determination unit 620 may obtain a firstradiation intensity corresponding to the first collimation width basedon the first scanning. In some embodiments, the acquisition module 510may obtain image data related to the object based on the first scanning.The image data of the first scanning may be associated with theradiations that pass through or be scattered by the experimental object.The relationship determination unit 620 may determine a first radiationintensity corresponding to the first collimation width based on theimage data of the first scanning.

In 1030, the CT scanner 110 may change the first collimation width to asecond collimation width. In some embodiments, the control module 520may instruct the CT scanner 110 to change the collimation width from thefirst collimation width to the second collimation width.

In 1040, the CT scanner 110 may perform a second scanning by scanningthe experimental object with the second collimation width.

In 1050, the relationship determination unit 620 may obtain a secondradiation intensity corresponding to the second collimation width basedon the second scanning. Step 1050 may be similar to step 1020 describedabove, and thus the description thereof will not be repeated here.

In 1060, the relationship determination unit 620 may obtain arelationship between radiation intensities and collimation widths basedon the first collimation width, the first radiation intensity, thesecond collimation width, and the second radiation intensity. Therelationship be may be recorded in the form of a table, a drawing, amathematical expression, etc. For example, the relationshipdetermination unit 620 may record the first collimation width and thecorresponding first radiation intensity, the second collimation widthand the corresponding second radiation intensity in a table and transmitthe table to a storage device (e.g., the storage module 530). As anotherexample, the relationship determination unit 620 may determine amathematical function based on the first collimation width and thecorresponding first radiation intensity, the second collimation widthand the corresponding second radiation intensity. In some embodiments,the mathematical function may be a linear function with the collimationwidth being an independent variable and the radiation intensity being adependent variable. In some embodiments, the relationship determinationunit 620 may determine a mathematical function according to a curvefitting technique.

In 1070, the relationship determination unit 620 may determine arelationship between collimation widths and scattered radiationintensities based on the relationship between collimation widths andradiation intensities. For illustration purpose, the relationshipbetween collimation widths and radiation intensities as described inconnection with operation 1060 may be described according to Equation(6) below:I=f(w)  Equation (6),where I refers to the radiation intensity, and w refers to thecollimation width.

The radiation intensity may be equal to a sum of a scattered radiationintensity and a primary radiation intensity. The primary radiationintensity of the experimental object may be constant, and the scatteredradiation intensity may be associated with the collimation width asdescribed elsewhere in this disclosure (e.g., FIGS. 4A and 4B and therelevant descriptions). When the collimation width is close to zero, thescatter radiation intensity may be close to zero and the radiationintensity may be roughly equal to the primary radiation intensity. Asused herein, “being roughly equal to” may indicate that the differencebetween the radiation intensity and the primary radiation intensity isat most 0.01%, 0.1% 2% or any other values of the radiation intensity.The relationship between collimation widths and scattered radiationintensities may be determined based on Equation (6) and be describedaccording to Equation (7) below:S=f(w)−f(w ₀)  Equation (7),where S refers to the scattered radiation intensity, w₀ refers to thecollimation width being equal to zero, and f (w₀) refers to the primaryradiation of the experimental object.

It should be noted that the above descriptions of process 1000 areprovided for the purposes of illustration, and not intended to limit thescope of the present disclosure. For persons having ordinary skills inthe art, various modifications and changes in the forms and details ofthe application of the above method and system may occur withoutdeparting from the principles of the present disclosure. However, thosevariations and modifications also fall within the scope of the presentdisclosure.

In some embodiments, operations 1030 to 1050 may be performed formultiple times to obtain multiple radiation intensities corresponding tomultiple collimation widths. In 1060, the relationship determinationunit 620 may obtain the relationship between collimation widths andradiation intensities based on the first collimation width, the firstradiation intensity, and the multiple collimation widths and theircorresponding radiation intensities. The determination of therelationship between collimation widths and radiation intensities may beperformed according on a curve fitting technique. For example, amathematical function recording the relationship between collimationwidths and radiation intensities may be determined based on the firstcollimation width, the first radiation intensity, and the multiplecollimation widths and their corresponding radiation intensitiesaccording to the curve fitting technique. The mathematical function mayinclude but is not limited to a linear function, an inverse function, aninverse function as described elsewhere in this disclosure (e.g., FIG. 8and the relevant descriptions).

In some embodiments, an additional operation may be performed todetermine the relationship between relationship between collimationwidths and ratios of scattered radiation intensities over the primaryradiation intensity as described elsewhere in this disclosure (e.g.,FIG. 8 and the relevant descriptions). The relationship betweencollimation widths and scattered radiation intensities may be determinedbased on Equation (7) and be described according to Equation (8) below:S=f(R*f(w ₀))−f(w ₀)  Equation (8),where S refers to the scattered radiation intensity, w₀ refers to thecollimation width being equal to zero, f (w₀) refers to the primaryradiation of the experimental object, and R refers to the ratio ofscattered radiation intensity over the primary radiation intensity.

Having thus described the basic concepts, it may be rather apparent tothose skilled in the art after reading this detailed disclosure that theforegoing detailed disclosure is intended to be presented by way ofexample only and is not limiting. Various alterations, improvements, andmodifications may occur and are intended to those skilled in the art,though not expressly stated herein. These alterations, improvements, andmodifications are intended to be suggested by this disclosure, and arewithin the spirit and scope of the exemplary embodiments of thisdisclosure.

Moreover, certain terminology has been used to describe embodiments ofthe present disclosure. For example, the terms “one embodiment,” “anembodiment,” and/or “some embodiments” mean that a particular feature,structure or characteristic described in connection with the embodimentis included in at least one embodiment of the present disclosure.Therefore, it is emphasized and should be appreciated that two or morereferences to “an embodiment” or “one embodiment” or “an alternativeembodiment” in various portions of this specification are notnecessarily all referring to the same embodiment. Furthermore, theparticular features, structures or characteristics may be combined assuitable in one or more embodiments of the present disclosure.

Further, it will be appreciated by one skilled in the art, aspects ofthe present disclosure may be illustrated and described herein in any ofa number of patentable classes or context including any new and usefulprocess, machine, manufacture, or composition of matter, or any new anduseful improvement thereof. Accordingly, aspects of the presentdisclosure may be implemented entirely hardware, entirely software(including firmware, resident software, micro-code, etc.) or combiningsoftware and hardware implementation that may all generally be referredto herein as a “unit,” “module,” or “system”. Furthermore, aspects ofthe present disclosure may take the form of a computer program productembodied in one or more computer readable media having computer readableprogram code embodied thereon.

A computer readable signal medium may include a propagated data signalwith computer readable program code embodied therein, for example, inbaseband or as part of a carrier wave. Such a propagated signal may takeany of a variety of forms, including electro-magnetic, optical, or thelike, or any suitable combination thereof. A computer readable signalmedium may be any computer readable medium that is not a computerreadable storage medium and that may communicate, propagate, ortransport a program for use by or in connection with an instructionexecution system, apparatus, or device. Program code embodied on acomputer readable signal medium may be transmitted using any appropriatemedium, including wireless, wireline, optical fiber cable, RF, or thelike, or any suitable combination of the foregoing.

Computer program code for carrying out operations for aspects of thepresent disclosure may be written in any combination of one or moreprogramming languages, including an object oriented programming languagesuch as Java, Scala, Smalltalk, Eiffel, JADE, Emerald, C++, C#, VB. NET,Python or the like, conventional procedural programming languages, suchas the “C” programming language, Visual Basic, Fortran 2103, Perl, COBOL2102, PHP, ABAP, dynamic programming languages such as Python, Ruby andGroovy, or other programming languages. The program code may executeentirely on the user's computer, partly on the user's computer, as astand-alone software package, partly on the user's computer and partlyon a remote computer or entirely on the remote computer or server. Inthe latter scenario, the remote computer may be connected to the user'scomputer through any type of network, including a local area network(LAN) or a wide area network (WAN), or the connection may be made to anexternal computer (for example, through the Internet using an InternetService Provider) or in a cloud computing environment or offered as aservice such as a Software as a Service (SaaS).

Furthermore, the recited order of processing elements or sequences, orthe use of numbers, letters, or other designations therefore, is notintended to limit the claimed processes and methods to any order exceptas may be specified in the claims. Although the above disclosurediscusses through various examples what is currently considered to be avariety of useful embodiments of the disclosure, it is to be understoodthat such detail is solely for that purpose, and that the appendedclaims are not limited to the disclosed embodiments, but, on thecontrary, are intended to cover modifications and equivalentarrangements that are within the spirit and scope of the disclosedembodiments. For example, although the implementation of variouscomponents described above may be embodied in a hardware device, it mayalso be implemented as a software only solution, for example, aninstallation on an existing server or mobile device.

Similarly, it should be appreciated that in the foregoing description ofembodiments of the present disclosure, various features are sometimesgrouped together in a single embodiment, figure, or description thereoffor the purpose of streamlining the disclosure aiding in theunderstanding of one or more of the various inventive embodiments. Thismethod of disclosure, however, is not to be interpreted as reflecting anintention that the claimed subject matter requires more features thanare expressly recited in each claim. Rather, inventive embodiments liein less than all features of a single foregoing disclosed embodiment.

In some embodiments, the numbers expressing quantities or propertiesused to describe and claim certain embodiments of the application are tobe understood as being modified in some instances by the term “about,”“approximate,” or “substantially.” For example, “about,” “approximate,”or “substantially” may indicate ±20% variation of the value itdescribes, unless otherwise stated. Accordingly, in some embodiments,the numerical parameters set forth in the written description andattached claims are approximations that may vary depending upon thedesired properties sought to be obtained by a particular embodiment. Insome embodiments, the numerical parameters should be construed in lightof the number of reported significant digits and by applying ordinaryrounding techniques. Notwithstanding that the numerical ranges andparameters setting forth the broad scope of some embodiments of theapplication are approximations, the numerical values set forth in thespecific examples are reported as precisely as practicable.

Each of the patents, patent applications, publications of patentapplications, and other material, such as articles, books,specifications, publications, documents, things, and/or the like,referenced herein is hereby incorporated herein by this reference in itsentirety for all purposes, excepting any prosecution file historyassociated with same, any of same that is inconsistent with or inconflict with the present document, or any of same that may have alimiting affect as to the broadest scope of the claims now or laterassociated with the present document. By way of example, should there beany inconsistency or conflict between the description, definition,and/or the use of a term associated with any of the incorporatedmaterial and that associated with the present document, the description,definition, and/or the use of the term in the present document shallprevail.

In closing, it is to be understood that the embodiments of theapplication disclosed herein are illustrative of the principles of theembodiments of the application Other modifications that may be employedmay be within the scope of the application. Thus, by way of example, butnot of limitation, alternative configurations of the embodiments of theapplication may be utilized in accordance with the teachings herein.Accordingly, embodiments of the present application are not limited tothat precisely as shown and described.

I claim:
 1. A system, comprising: a scanner having a collimator, acollimation width of the collimator being adjustable; one or morenon-transitory storage devices including a set of instructions for imagedata processing; and at least one processor configured to communicatewith the one or more non-transitory storage devices, wherein whenexecuting the set of instructions, the at least one processor isconfigured to cause the system to: obtain a relationship betweencorrection coefficients and collimation widths; obtain a targetcollimation width of the collimator; and determine a target correctioncoefficient based on the target collimation width and the relationshipbetween correction coefficients and collimation widths, wherein toobtain the relationship between correction coefficients and collimationwidths, the at least one processor is configured to cause the system to:obtain a first correction coefficient, the first correction coefficientcorresponding to a first collimation width of the collimator; obtain arelationship between scattered radiation intensities and collimationwidths; and determine the relationship between correction coefficientsand collimation widths based on the first correction coefficient, thefirst collimation width, and the relationship between scatteredradiation intensities and collimation widths.
 2. The system of claim 1,the at least one processor is configured to cause the system to: obtainimage data related to a scanning with the target collimation width; andmodify the image data based on the target correction coefficient.
 3. Thesystem of claim 1, wherein the at least one processor is furtherconfigured to cause the system to save the determined relationshipbetween correction coefficients and collimation widths to the one ormore non-transitory storage devices.
 4. The system of claim 1, whereinto obtain the first correction coefficient corresponding to the firstcollimation width, the at least one processor is configured to cause thesystem to: instruct the scanner to scan a first object with the firstcollimation width; obtain image data related to the first object basedon the scanning of the first object; process the image data related tothe first object; reconstruct an image of the first object based on theprocessed image data related to the first object; and determine thefirst correction coefficient corresponding to the first collimationwidth based on the reconstructed image of the first object.
 5. Thesystem of claim 4, wherein the first object is a water phantom.
 6. Thesystem of claim 4, wherein to instruct the scanner to scan the firstobject with the first collimation width, the at least one processor isconfigured to cause the system to: instruct the scanner to scan air withthe first collimation width.
 7. The system of claim 1, wherein to obtainthe relationship between scattered radiation intensities and collimationwidths, the at least one processor is configured to cause the system to:instruct the scanner to perform a first scanning of a second object witha second collimation width; obtain a first radiation intensity based onthe first scanning of the second object; instruct the scanner to changethe collimation width from the second collimation width to a thirdcollimation width; instruct the scanner to perform a second scanning ofthe second object with the third collimation width; obtain a secondradiation intensity based on the second scanning of the second object;determine the relationship between radiation intensities and collimationwidths based on the second collimation width, the first radiationintensity, the third collimation width, and the second radiationintensity; and determine the relationship between scattered radiationintensities and collimation widths based on the determined relationshipbetween radiation intensities and collimation widths.
 8. The system ofclaim 7, wherein the determination of the relationship between radiationintensities and collimation widths based on the second collimationwidth, the first radiation intensity, the third collimation width, andthe second radiation intensity is performed according to a curve fittingtechnique.
 9. The system of claim 7, wherein to determine therelationship between scattered radiation intensities and collimationwidths based on the relationship between radiation intensities andcollimation widths, the at least one processor is configured to causethe system to: determine a primary radiation intensity of the secondobject based on the relationship between radiation intensities andcollimation widths.
 10. The system of claim 9, wherein to determine therelationship between scattered radiation intensities and collimationwidths, the at least one processor is configured to cause the system to:obtain a relationship between collimation widths and ratios of scatteredradiation intensities over the primary radiation intensity of the secondobject; and designate the relationship between collimation widths andratios of scattered radiation intensities over the primary radiationintensity of the second object as the relationship between scatteredradiation intensities and collimation widths.
 11. A computer-implementedmethod for image data processing, the method comprising the followingoperations performed by at least one processor: obtaining, by the atleast one processor, a relationship between correction coefficients andcollimation widths; obtaining, by the at least one processor, a targetcollimation width of a collimator of a scanner; and determining, by theat least one processor, a target correction coefficient based on thetarget collimation width and the relationship between correctioncoefficients and collimation widths, wherein obtaining the relationshipbetween correction coefficients and collimation widths furthercomprises: obtaining a first correction coefficient, the firstcorrection coefficient corresponding to a first collimation width of thecollimator; obtaining a relationship between scattered radiationintensities and collimation widths; and determining the relationshipbetween correction coefficients and collimation widths based on thefirst correction coefficient, the first collimation width, and therelationship between scattered radiation intensities and collimationwidths.
 12. The method of claim 11, further comprising: obtaining imagedata related to a scanning with the target collimation width; andmodifying the image data based on the target correction coefficient. 13.The method of claim 11, wherein obtaining the first correctioncoefficient corresponding to the first collimation width furthercomprises: scanning, by the scanner, a first object with the firstcollimation width; obtaining, by the at least one processor, image datarelated to the first object based on the scanning of the first object;processing, by the at least one processor, the image data related to thefirst object; reconstructing, by the at least one processor, an image ofthe first object based on the processed image data related to the firstobject; and determining, by the at least one processor, the firstcorrection coefficient corresponding to the first collimation widthbased on the reconstructed image of the first object.
 14. The method ofclaim 11, wherein obtaining the relationship between scattered radiationintensities and collimation widths further comprises: performing, by thescanner, a first scanning of a second object with a second collimationwidth; obtaining, by the at least one processor, a first radiationintensity based on the first scanning of the second object; changing, bythe scanner, from the second collimation width to a third collimationwidth; performing, by the scanner, a second scanning of the secondobject with the third collimation width; obtaining, by the at least oneprocessor, a second radiation intensity based on the second scanning ofthe second object; determining, by the at least one processor, therelationship between radiation intensities and collimation widths basedon the second collimation width, the first radiation intensity, thethird collimation width, and the second radiation intensity; anddetermining, by the at least one processor, the relationship betweenscattered radiation intensities and collimation widths based on thedetermined relationship between radiation intensities and collimationwidths.
 15. The method of claim 14, wherein determining the relationshipbetween radiation intensities and collimation widths based on the secondcollimation width, the first radiation intensity, the third collimationwidth, and the second radiation intensity is performed according to acurve fitting technique.
 16. The method of claim 15, wherein determiningthe relationship between scattered radiation intensities and collimationwidths further comprises: obtaining, by the at least one processor, arelationship between collimation widths and ratios of scatteredradiation intensities over the primary radiation intensity of the secondobject; and designate the relationship between collimation widths andratios of scattered radiation intensities over the primary radiationintensity of the second object as the relationship between scatteredradiation intensities and collimation widths.
 17. The method of claim14, wherein determining the relationship between scattered radiationintensities and collimation widths based on the relationship betweenradiation intensities and collimation widths further comprises:determining, by the at least one processor, a primary radiationintensity of the second object based on the relationship betweenradiation intensities and collimation widths.